INtroduce compression class to encapsulate compression via zlib

2022-02-06 20:42:58 +01:00
parent ecfb9757d0
commit 9335cc30ab
11 changed files with 270 additions and 67 deletions
@@ -0,0 +1,141 @@
+/*
+Open Asset Import Library (assimp)
+----------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the
+following conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+----------------------------------------------------------------------
+*/
+
+#include "Compression.h"
+#include <assimp/ai_assert.h>
+#include <assimp/Exceptional.h>
+
+#ifdef ASSIMP_BUILD_NO_OWN_ZLIB
+#include <zlib.h>
+#else
+#include "../contrib/zlib/zlib.h"
+#endif
+
+namespace Assimp {
+
+struct Compression::impl {
+    bool mOpen;
+    z_stream mZSstream;
+
+    impl() :
+            mOpen(false) {}
+};
+
+Compression::Compression() :
+        mImpl(new impl) {
+    // empty
+}
+
+Compression::~Compression() {
+    ai_assert(mImpl != nullptr);
+
+    delete mImpl;
+}
+
+bool Compression::open() {
+    ai_assert(mImpl != nullptr);
+
+    if (mImpl->mOpen) {
+        return false;
+    }
+
+    // build a zlib stream
+    mImpl->mZSstream.opaque = Z_NULL;
+    mImpl->mZSstream.zalloc = Z_NULL;
+    mImpl->mZSstream.zfree = Z_NULL;
+    mImpl->mZSstream.data_type = Z_BINARY;
+
+    // raw decompression without a zlib or gzip header
+    inflateInit2(&mImpl->mZSstream, -MAX_WBITS);
+    mImpl->mOpen = true;
+
+    return mImpl->mOpen;
+}
+
+constexpr size_t MYBLOCK = 1024;
+
+size_t Compression::decompress(unsigned char *data, size_t in, std::vector<unsigned char> &uncompressed) {
+    ai_assert(mImpl != nullptr);
+
+    mImpl->mZSstream.next_in = reinterpret_cast<Bytef *>(data);
+    mImpl->mZSstream.avail_in = (uInt)in;
+
+    Bytef block[MYBLOCK] = {};
+    int ret = 0;
+    size_t total = 0l;
+    do {
+        mImpl->mZSstream.avail_out = MYBLOCK;
+        mImpl->mZSstream.next_out = block;
+        ret = inflate(&mImpl->mZSstream, Z_NO_FLUSH);
+
+        if (ret != Z_STREAM_END && ret != Z_OK) {
+            throw DeadlyImportError("Compression", "Failure decompressing this file using gzip.");
+
+        }
+        const size_t have = MYBLOCK - mImpl->mZSstream.avail_out;
+        total += have;
+        uncompressed.resize(total);
+        ::memcpy(uncompressed.data() + total - have, block, have);
+    } while (ret != Z_STREAM_END);
+
+    return total;
+}
+
+bool Compression::isOpen() const {
+    ai_assert(mImpl != nullptr);
+
+    return mImpl->mOpen;
+}
+
+bool Compression::close() {
+    ai_assert(mImpl != nullptr);
+
+    if (!mImpl->mOpen) {
+        return false;
+    }
+
+    inflateEnd(&mImpl->mZSstream);
+    mImpl->mOpen = false;
+
+    return true;
+}
+
+} // namespace Assimp